Valve lifter



April 24, 1945. J. D. SMITH VALVE LIFTER Fi'led Jam-5, 1944 VIVA? Patented Apr. 24, 1945 UNITED STATES PATENT OFFICE VALVE LIFTER as D. Smith, Decatur, Ga.

Application January 5, 1944, Serial No. 517,092

4 Claims.

This invention relates to valve lifters for internal combustion engines, and has for-the primary object the provision of a hydraulic lifter readily adaptable to an engine between the usual valve cam and the intake or exhaust valves of said engine and provides for greater travel of the valve relative to its seat, providing better engine performance than is attainable by a conventional type of mechanical lifter and provides quieter valve operations and fully compensates for expansion and contraction which may take place in the valve mechanism of theengine, and which assures against improper seating of the valve or the opening thereof. i

With these and other objects in view as willbecome more apparent as the description proceeds, the invention consists in certain novel features of construction, combination and arrangement of parts as will be hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had to the following description and accompanying drawing, in which Figure 1 is a vertical sectional view illustrating a hydraulic valve lifter for an internal combustion engine constructed in accordance with my invention and showing the same associated with a valve cam and the stem of a valve.

Figure 2 is a sectional view taken on the line 2-2 of Figure 1.

Referring in detail to the drawing, the numeral 5 indicates a cylinder fully open at one end and provided with a head 6 at its opposite end. The head has an attaching flange 'l apertured to receiyefasteners 8 for mounting the cylinder in a wall 9 of an internal combustion engine. The open end of the cylinder when mounted in the engine is disposed over the cam shaft Ill of the valvemechanism of said engine. The head 6 has a centrally arranged passage therethrough in which i slidably mounted a valve operating rod or push rod ll provided with a screwthreaded socket l2 opening outwardly throughits upper end to receive a tappet is including alock nut Id. The tappet threads into the socket I2 and is adjustable endwise of the push rod so that a desired clearance may be had between the tappet head and the lower end of an intake valve 1 or exhaust valve of the engine, the stem of which isindicated by the character l5 and a spring element is shown conventionall coiled about the stem in abutting relation to and supported by a collar I5" pinned or otherwise secured on the stem, which spring element, in use, holds the valve (not shown) yieldably in its closed position and restores it to such position after each opening actuation thereof. The tappet [3 has a pas sage l3 drilled therein and extends from end to end thereof. A passage lfiis formed axially inthe push rod and communicates at its upper end with the screw threaded socket l2 and opens outwardly and laterally at its lower end through a side of the push rod within the cylinder 5 as at It. The purpose of the lateral passage l6 and the communicating longitudinal passage drilled in the tappet assembly as at It is to vent the cylinder 5 when the push rod II is permitted to assume its lowermost position by a cam I! on the cam shaft l0 and the cylinder is receiving liquid. In this connection, it is here noted that the passage l3' in the tappet plug l3 (indicated in. dotted lines in Figure 1) is a small axial bore which, at all times, is in communication with the socket l2 in the push rod ll, whereby to serve as a vent opening, except while the engineis running and as will be later more fully described. To limit the downward movement of the push rod II in the cylinder, the push rod is provided with an annular groove I 8 ,in which snaps a spring influenced ball l9 when the push rod moves to its fullest lowermostposition during the normal operation of the valve by the lifter.

A spider 20 is formed on the cylinder 5 and supports the push rod slidably therein and provides a mounting for the spring pressed ball I9, also a mounting for a ball type spring influenced check valve 2!. Opposite to the spider .20 and connecting therewith is a boss 22 which forms a part on the outside of the cylinder. The boss 22 is internally threaded to receive a removable seat 23 for the check valve 2! and has a liquidpressllre supply pipe 24 threaded thereto. The check valve 2| will admit liquid from the pipe 24 to the cylinder, but will prevent the liquid from returning to said pipe. The spider 20 has ports 20' and 2|. The ports 20' and 2 I only communicate with the annular groove I8 when the valve of the engine engages its seat, that is to say, when the ball I9 is in said annular groove, so that the cylinder receives the liquid from pipe 24 only during the time that the valve of the engine is in seated position. When the valve of the engine leaves its seat and at all times when fully disengaged from said seat, the groove I8 is out of communication with the, ports 20' and 2! and the push rod H acts to close said ports 20 and 2| cutting off the liquid to the cylinder.

The liquid in the cylinder is acted on by a plunger 25 which is slidable longitudinally in said cylinder and is provided with a head 26 at its cylinder through leakage, if such occurs.

ever, this arrangement will assure the cylinder being kept full of liquid during the period of opthe fact thatthe cylinder is permitted to receive liquid from the supply only. when said cylinder is vented and the engine valve is closed and otherwise only intermittently during the operation of the engine if there is room for more liquid in the Howeration of the engine.

In this connection, it is here noted that the cylinder '5 is vented only prior to the starting of operation of the engine, and that the passageway 16 is closed by the tappet member l3 being moved into contact with the lower end of the valve stem l5 immediately after starting of operationof the engine and the same remains closed during operation of the engine because of the cylinder 5 having been filled with liquid under pressure at the outset and is so maintained .during operation through the supply pipe 24 and the ports and 2|! if more liquid is needed or there is room for the same in the cylinder 5 .as the annular groove I8 in thepush rod 1] is brought intermittently into register with said ports 20! and 2| To prevent leakage between the plunger and the walls of the cylinder, a cupshaped washer 21 is detachably secured tothe inner end of the plunger and rides against the walls of the cylinder. To sustain the washer 2,1 spread against the walls of the cylinder, a plate 28forming a part of the fastening means of the washer to the plunger is provided. The plate 28 also provides a solid surface for a projection 29 on the lower end of the push rod to contact should the push rod be moved below its normal lowermost position controlled by the ball 19 engaging in the groove l8 of the push rod, so that a substantial clearance 30 will be provided at all times between the plunger 25and the lower end of the push rod. Normally this clearance should be at least between thirty to forty thousandths of an inch but,

of course, this dimension may bevaried in different adaptations of the invention.

The liquid pressure supply pipe 24 may be connected to the lubricant pressure pump of the engine or, obviously, to any other suitable source of supply, even if necessarily provided especially for thepurposes of the invention, so that the cylinder 5 will be furnished with liquid under end of the push rod next to the plunger, the push rod will travel faster and for a greater distance than the distance of travel of the plunger as the position, resulting in better engine performance.

It is to be understood that as the high portion of the cam I! leaves the head 26 of the plunger 25, the spring of the engine valve (not shown) acts to close the engine valve or to move said engine valve into a full seated position as soon as the head of the plunger is in contact with the pressure during the time of operation of the eng ne.

The instant the plunger 25 is moved upwardly by'the cam ll, the communicationof the vent passage [Swith the cylinder 5 is closed by contact of the tappet element l-3 with the lower end of the valve stem l5, so that the liquid inthe cylinder from thepipe 24 will be trapped in said cylinder. The plunger 25 acting on the column of liquid trapped inthe cylinder 5, causes the liquid in turn to act on the push rod I 6 thus bringing about unseating of the valve of the engine. As the area. of the plungerwhich actson the trapped liquid greatly exceeds the area of the low portion of the cam. The plunger movement is governed entirely by the cam ll. However, the downward movement of the push rod 1 l is checked by the spring influenced ball l9 entering thegroove l8 of the push rod. The engine valve is at this time in a fully seated and closed positionand the cylinder 5 at this time is vented and receiving liquid from the pipe 24 keeping said cylinder filled with the liquid.

As there is always liquid between the plunger 25and the end of the push rod 'H it assures a quiet operation of said parts and also will permit a closer adjustment to be used between the tappet assembly 13 and the stem 15 ofthe enginevalve, which all tends to provide a quieter valve opera- .tion.

While I have shown and described the preferred embodiment of my invention, it will be understood that minor changes in construction, combination and arrangementof parts may be made without departing from the spirit and scope of the inventionas claimed.

Having thus described the invention, what I inder and including an adjustable tappet assembly in one endof the push rod adapted to provide a selected clearance between vsaidpush rod and the valve when the push rod i at the end of its stroke in one direction, a plunger operated by the cam and slidable in the cylinder, said push rod having an annular groove, a spring projected ball carried by the cylinder and adapted to seat in said groove for checking the movement of said push rod in said direction to provide a clearance between the push rod and the plunger, and a liquid pressure supply. connected to the cylinder for filling the space in the cylinder andthe space between the plunger and the push rod with liquid.

2. In combination with a valve for an internal combustion engine and a cam'for operating said valve, a cylinder, a push rod slidablein the cylinder and including an adjustable tappet assembly in one end of the push rod adapted to provide a selected clearance between said push rod and the valve when the push rod isv at the end of its-stroke in one direction, a plunger operated by the cam and slidable in the cylinder, said push rod have ing an annular groove, a spring projected ball 'carried by the cylinder and adapted to seatin valve, a cylinder, a push rod slidable in the cylinder and including an adjustable tappet assembly in one end of the push rod adapted to provide a selected clearance between said push rod and i the valve when the push rod is at the end of its valve acting to prevent liquid from being returned to the supply from the cylinder by the movement of the plunger, said push rod. and tappet assembly having communicating vent passages and the vent passage of the push rod connecting with the cylinder only during the time the push rod is at the end l of said stroke and the cylinder is receiving liquid.

4. In combination with a valve for an internal combustion engine and a cam for operating said valve, a cylinder, 2, push rod slidable in the cylinder and including an adjustable tappet assembly in one end of the push rod adapted to provide a selected clearance between said push rod and the valve when the push rod is at the end of its stroke in one direction, a plunger operated by the cam and slidable in the cylinder, 2. liquid supply means connected to the cylinder for furnishing the cylinder and the space between the plunger and the push rod with liquid, said push rod having an annular groove, a spring projected ball carried by the cylinder and adapted to seat in said groove for checking the'movement of said push rod in said direction and thereby providing a clearance between the push rod and the plunger, the area of the plunger acting on the liquid in the cylinder being much greater than the area of the end of the pushrod opposingsaid plunger.

' JEFF D. SMITH. 

